"Today would have been your 50th birthday," the post read. "You are loved and you are missed. Thank you for giving me the GIFT of life."
She signed the note, "Forever your daughter, Frances Bean Cobain," and added the caption, "February 20th 2017. Happy Birthday."
She also shared a screengrab of an emotional text message in conversation with her grandmother, Wendy Cobain. In it, she thanks Kurt's mother for being her "one and only" and for raising her to be "strong and compassionate."
Wendy responded, "You were such a caring loving little girl and have turned into such a beautiful young woman," noting how Kurt would be so "smugly" proud of his daughter.
"Not gonna lie, I cried a little," she captioned the post. "I love you grams."
"I first met Frances Bean when she was 2 years old at a dinner with her mom (Courtney) and Anna Sui in 1994 at Bar Six in NYC," the designer recalled on social media. "I have always wanted to work with Frances. Her beauty, uniqueness, and strength is something I have long admired and respected. Few things remain as constant as my continued inspiration from those whose honesty, integrity, courage, and curiosity lead them to explore and venture beyond preconceived boundaries."